THE RATS AND MICE glandular swelling at the base of the oesophagus, such as occurs in the last genus and in GrapJiiurus. Of Gra/phiurus there are thirteen species, all African in range. The genus does not differ widely from the last. There is, however, a glandular region of the oesophagus. JZliomys is the last genus of typical Dormice. It is Palaearctic in range. Platacantho'mys, of a Dormouse -like form, has like other Dormice a long tail, on which the long coarse hairs are arranged in two rows on opposite sides towards the tip ; it is represented by a single species, P. lasiur^, from the Malabar coast. It is arboreal in habit. The fur is mingled with flattened spines, The molars are reduced to three on each side of each jaw. This form has been bandied about between the " Mice " and the " Dormice " ; but Mr. Thomas's discovery of the absence of the caecum argues strongly in favour of its correct location among the Gliridae. TypMomys is an allied genus, also from the Oriental region. This and the last are placed in a special sub-family of the Gliridae, Platacanthomyinae, by Mr. Thomas. Fam. 2. Miiridae. — This family, that of the TŁats and Mice in a wide sense, is the most extensive family of Eodents. In it Mr. Thomas includes no less than seventy -six genera. The molars are generally three. The tail is fairly long, or very long, and the soles of the feet are naked. Sub-Fam. i« Murinae. — The true Rats and Mice may be considered to form, a sub -family, Murinae. The genus Mus, including the Eats and Mice in the limited sense of the word, contains about 130 species. They are exclusively Old World in range, being only absent from the Island of Madagascar. In the New World there are no species of the restricted genus Mus. The eyes and the ears are large ; the pollex is rudimentary, and bears a nail instead of a claw. The tail is largely scaly. All the members of the genus are small animals, some quite minute. In this country there are five species1 of the genus, viz. the Harvest Mouse, M. minutus, which has a body only 2^ inches long with an equally long tail. It is the smallest of British quadrupeds with the exception of the Lesser Shrew. The Wood Mouse, M. sylvaticus, is about twice the size ; it differs also from the last species in that; it 1 To which a sixth, the "Yellow-necked Mouse,'* Mus flasoicoUis, may perhaps be added.